Automatic water unloader



Patented Jan. 9, 1951 UNITED STATES PATENT orrics 2,537,224 AUTOMATIC WATER UNLOADER William M. Lans'cla'le and Conrad R. B'lichet',

' Los- Angeles, Calif.

Application March 10, 1948, Serial No. 14,044

6 Claims.- 1

This invention relates to means for ridding air compressors of accumulations of water and contemplates employing built-up pressure in the compressor for automatically accomplishing the same.

Electrically operated air compressors, conventionally, comprise an air compressing unit that is driven by an electric motor to store compressed air in a tank from which said air is drawn as needed. When the pressure in the tank falls below apredetermined low pressure point, the motor starts up to operate the oriipressor unit to raise the pressure in the tank. The motor, then, auto-' matically stops when the pressurein the tank reaches a predetermined high pressure point. During operation, air pressure is built up in both the tank and in the compressor unit The latter, therefore, ofi'ers high torque resistance to the electric motor'when it seeks to start up. Accordingly, a pressure unloader' is typically provided for the compresso unit so that the same is,- in effect, vented. This relief of pressure in the compressor unit enables the motor to start up without undue load. Once started, the motor is capable or efiiciently operating the compressor unit.

Heretofore, this pressure that is relieved from the compressor unit is released to atmosphere. According to this invention, and it is an object thereof; this otherwise wasted compressed air is utilized for the purpose of ridding the tank of such Water that results when air is compress d.

Another object or the invention is to provide a novel water iinioader' that is connected to a com-pressed air tank and is operated by the pressure unloader of a co pressor unit for said tank.

A further object of the invention is to provide such a water Uri-loader that embodies adjustable means for controlling the time duration of its operation.

Oi'ir invention also has for its objects to provide such means that are positive in operation, convenient inuse, easily installed in a working position and easily disconnected therefrom, e00: nomical of manu acture, relatlve'l y's-impl', and of general super'ior'ity and serviceability.

The invention also comprises novei details of construction and novel combinations and arrangements of parts, which will more fully appear in the course of the following description. However, the drawings merely show and the following descriptionmerely describes one embodiment or the present invention, which is given by Way of illustration or example only.

In the drawings, like reference characters designate similar parts the several views.

Fig. 1 is a side elevational view of a conventional air compressor that embodies the water unloader of the present invention.

Fig. 2 is an enlarged longitudinal sectional view of the Water unloader unit in which is embodied adjustable means for controlling the duration of operation.

Fig. 3 is a fragmentary view of said unit showing unadjustable clearance controlling the duration of operation.

With more particular reference to Fig. 1, the air compressor shown comprises an air tank 5 into which is directed compressed air by a com press'or'u'nit 6 that is driven by an electric motor 1. conventionally, the compressor unit 6 is provided with a pressure unloader 8 for the reasons above stated. The foregoing conventional compressor is provided with a water unloader 9 and the same is connected by a tube ill to the pressure unloader, so that pressure relieved from the compressor unit 6 operates the unloader 9.

Fig. 2 shows said unloader in detail and the same comprises, generally, a body II, a fitting [2 for connecting the body to a nipple [3 (Fig. 1) that extends downward from the bottom of the tani z 5-, a valve [4' within the body and controlling flow from said tank, a piston i5 connected to the valve and in the path of flow of compressed air in tube !0 for operating said valve to release flow from the tank through an outlet It, means I! for restorin the valve to closed position automatically uponrelease of air pressure on the piston, and adjustable means ill for metering the release of said air pressure to thereby control the time during which the valve is open.

The body I l comprises a tubular part l9 that has an axial passage 29. The tube 10, by means of anut 2i, is connected to the body part [9 so that air pressure will enter through passage 20 and into the chamber 22 thereof. Body part l9, near the end opposed to passage 20, has a threaded seat 2 3 for the outlet I 6. Said latter end of the body is provided with internal threads for connection with an adapter part N that comprises part of the body ll. Said adapter part has a threaded extension 25 for connection to fitting f2.

An axial bore 26 is formed in part 24 and across said bore or in any suitable manner, there is provided a screen 21. Said screen is in the path of flow of water from tank It] and serves to prevent scale and other foreign matter from entering bore 26.

The valve 14 comprises a bushing 28 that is fitted intobore 26, said bushing' having an axial,

preferably round passage 29. The end of said bushing that is directed toward fitting I2 is formed to have a transverse valve seat 30. The seating part of the valve I4 comprises a compressible valve disc 3I that has flat engagement with valve seat 30'and a metallic retainer 32 for said disc.

A polygonal valve stem 33, in this case square, extends through bore 29 and has a cylindrical threaded extension 34 for mounting the valve disc 3I and retainer 32. A nut 35 serves to lock the latter in place on the stem 33.

The piston I is considerably larger in diameter than retainer 32 and the same is mounted on a reduced extension 36 of stem 33 and locked in place by a nut 31. The housing part I9 is machined with a smooth cylinder wall 38 and said piston is machined to operate therein with clearance 38*, as shown in Fig. 3, sufiicient to permit a slow flow of compressed air from chamber 22 into and out of outlet IS.

The means I1 is shown as a coiled compression spring about stem 33 and arranged between bushing 28 and piston I5, the spring acting to urge the piston in a direction to cause valve I4 to close.

From the foregoing construction it will be seen that when the compressor unit 6 automatically unloads its pressure, th s pressure is directed by tube II] to enter chamber 22 and act against the face of piston I5. The latter is forced back against the pressure of spring I1 and valve I4 opens so that any water there may be in the bottom of tank 5, under the pressure in said tank, is blown out past valve I4, through passage 29, out through fitting I5 and a tube 39 on the outlet side thereof. Since the piston is fitted with some clearance as stated, the unloading pressure passes between the piston and wall 38 to become dissipated in a matter of a few seconds so that spring I1 is then enabled to close valve I4 and close tank I5 against further discharge therefrom.

As shown in Fig. 2, a variation of the above may be provided for effecting control of the time that the valve I4 remains open. The piston I5 is fitted more closely to have only sliding clearance with wall 38 or, even a sealing r ng may be provided to obviate leakage around the piston. The adjustable means I8 is then provided to control the rate at which the unloading pressure dissipates. Means I8 is shown as a metering pin 40 that is threadedly extended through the wall of housing part I9, is locked in adjusted pos tion by a nut M, and has a tapered end 42 that fits into an opening 43 in the piston. The cylindrical part of pin 43 effectively closes said opening, but when the piston is forced back by unloading pressure, said opening becomes aligned with the tapered end 42 to provide an annular port for bleeding said pressure. Consequently, the size of said port depends on the adjusted position of means I8 and controls the duration that valve I4 is open. In the instance where little water is formed in tank 5, pin 40 is retracted for a rapid dissipation of the unloading pressure, and where much water is formed, a forwardly adjusted position of pin 40 causes a longer open time for valve I4.

While we have illustrated and described what we now regard as the preferred embodiment of our invention, the construction is, of course, subject to modifications without departing from the spirit and scope of our invention. We, therefore, do not wish to restrict ourselves to the particular form of construction illustrated and describe 4 but desire to avail ourselves of all modifications that may fall within the scope of the appended claims.

Having thus described our invention, what we claim and desire to secure by Letters Patent is:

1. A water unloader for compressed air tanks comprising a body connected to the bottom of said tank and having a passage for flow therefrom, a normally closed valve controlling said passage, a piston connected to the valve, and means for conducting fluid under pressure to act on said piston and open the valve, said body having a cylinder bore in which said piston is fitted with sufficient looseness to permit leakage of pressure around the piston whereby said pressure is rapidly dissipated and the valve is thereby opened momentarily.

2. A water unloader for compressed air tanks comprising, in combination, a body connected to the bottom of said tank and having a passage for flow therefrom, a normally closed valve controlling said passage, pressure responsive means within the body and connected to the valve to open the same momentarily, and means adjustably carried by the body and controlled from the outside thereof, said latter means having adjustable metering engagement with the pressure responsive means to control pressure flow past the latter means for controlling the time that the valve is open.

3. A water unloader for compressed air tanks comprising a body connected to the bottom of said tank and having a passage for flow therefrom, a normally closed valve controlling said passage, a piston connected to the valve, means for conductng fluid under pressure to act on said piston and open the valve, said piston having an opening therein, and adjustable means extending into said opening for controlling pressure flow therethrough and thereby the time that said valve is open.

4. A water unloader for compressed air tanks comprising a body connected to the bottom of said tank and having a passage for flow therefrom, a normally closed valve controlling said passage, a piston connected to the valve, means for conducting fiuid under pressure to act on said piston and open the valve, said piston having an opening therein, and adjustable means extending into said opening for controlling pressure flow therethrough and thereby the time that said valve is open, said means comprising a tapered metering pin that varies the effective size of the port formed by said pin and the opening into which it extends.

5. An automatic water unloader comprising a hollow body having a cylindr cal passage therein, a polygonal stem in said passage, a valve on one end of the stem, a piston on the other end, a spring for urging said piston and valve in one direction to close the passage to flow, and means for conducting fluid under pressure to act on said piston in a direction to open sa d valve against the force of said spring, said piston being so loosely fitted in the body that said fluid pressure is rapidly dissipated, whereby the spring becomes automatically effective to close the valve.

6. An automatic water unloader comprising a hollow body having a cylindrical passage therein, a polygonal stem in said passage, a valve on one end of the stem, a piston on the other end, a spring for urging said piston and valve in one direction to close the passage to flow, means for conducting fluid under pressure to act on said pistonina direction to open said valve against 5 the force 01 said spring, said piston being so loosely fitted in the body that said fluid pressure is rapidly dissipated, whereby the spring becomes automatically effective to close the valve, and adjustable means for controlling the rate of dissipation of the fluid pressure to control the time that said valve is open.

WILLIAM M. LANSDALE. CONRAD ROBERT BUCKET.

6 REFERENCES crriin The following references are Of'ree'ord in the file of this patent:

UNITED STATES PATENTS Number 

